Ruby-EnumRuby 快速定义枚举-技术圈

Ruby-Enum 是一组 Ruby 定义枚举的便捷方式，可用于快速定义枚举。

用法

枚举可以作为常量或类方法定义和访问。

常量

定义枚举，并作为常量引用



class OrderState

  include Ruby::Enum



  define :CREATED, 'created'

  define :PAID, 'paid'

end



OrderState::CREATED # 'created'

OrderState::PAID # 'paid'

OrderState::UNKNOWN # raises Ruby::Enum::Errors::UninitializedConstantError

OrderState.keys # [ :CREATED, :PAID ]

OrderState.values # [ 'created', 'paid' ]

OrderState.to_h # { :CREATED => 'created', :PAID => 'paid' }

类方法

定义枚举，并作为类方法引用



class OrderState

  include Ruby::Enum



  define :created, 'created'

  define :paid, 'paid'

end



OrderState.created # 'created'

OrderState.paid # 'paid'

OrderState.undefined # NoMethodError is raised

OrderState.keys # [ :created, :paid ]

OrderState.values # ['created', 'paid']

默认值

指可选，不选的话默认为 key。



class OrderState

  include Ruby::Enum



  define :UNSPECIFIED

  define :unspecified

end



OrderState::UNSPECIFIED # :UNSPECIFIED

OrderState.unspecified # :unspecified

枚举

支持所有Enumerable方法

迭代



OrderState.each do |key, enum|

  # key and enum.key are :CREATED, :PAID

  # enum.value is 'created', 'paid'

end



OrderState.each_key do |key|

  # :CREATED, :PAID

end



OrderState.each_value do |value|

  # 'created', 'paid'

end

映射



OrderState.map do |key, enum|

  # key and enum.key are :CREATED, :PAID

  # enum.value is 'created', 'paid'

  [enum.value, key]

end



# => [ ['created', :CREATED], ['paid', :PAID] ]

排序



OrderState.sort_by do |key, enum|

  # key and enum.key are :CREATED, :PAID

  # enum.value is 'created', 'paid'

  enum.value.length

end



# => [[:PAID, #<OrderState:0x0 @key=:PAID, @value="paid">], [:CREATED, #<OrderState:0x1 @key=:CREATED, @value="created">]]